Structures of the O-antigens of Proteus bacilli belonging to OX group (serogroups O1-O3) used in Weil-Felix test

Structures of the O-specific polysaccharide chains of lipopolysaccharides from Proteus group OX strains (serogroups O1-O3) used as antigens in Weil-Felix test for diagnosis of rickettsiosis, were established. From them, the acid-labile polysaccharide of Proteus vulgaris OX19 (O1) is built up of the following branched pentasaccharide repeating units connected via a phosphate group: [structure in text] where QuiNAc stands for 2-acetamido-2,6-dideoxyglucose (N-acetylquinovosamine). The basis of serospecificity of the Proteus group OX antigens and their cross-reactivity with human anti-rickettsial antibodies is discussed.     

Newer anticonvulsant drugs: role of pharmacology, drug interactions and adverse reactions in drug choice

In the last few years a number of new anticonvulsants have been introduced into clinical practice mainly as add-on therapy in patients who do not become seizure-free while receiving established anticonvulsants. Up to now, no single drug has been shown to be more effective at controlling seizures of a particular type than another, so other factors such as mechanism of action, pharmacokinetics, dosage regimens or the spectrum of adverse drug reactions and interactions are used when making a choice between one agent and another. The mechanism of action of tiagabine and vigabatrin is very specific; both agents increase gamma-aminobutyric acid (GABA) levels through inhibition of reuptake and catabolism respectively. However, the mechanism of action of gabapentin is unknown and those of felbamate, lamotrigine and topiramate are not sufficiently clarified as yet, and may be multiple. Great advances have been made in improving the pharmacokinetic characteristics of these newer anticonvulsants. Gabapentin and vigabatrin exhibit relatively ideal pharmacokinetic properties as they are not bound to proteins, are excreted mostly unchanged in the urine and show linear pharmacokinetics. Lamotrigine possesses a highly variable elimination half-life depending on the co-medication. Tiagabine is highly protein bound and zonisamide shows nonlinear pharmacokinetics; both these drugs are extensively metabolised. Problematic drug interactions between newer anticonvulsants and other drugs in general occur rarely when these agents are given concomitantly. However, in common with most new drugs, there are very few data on the use of the newer anticonvulsants in women of childbearing age. Studies done so far on interactions with oral contraceptives used low anticonvulsant dosages for a very short time. The newer anticonvulsants elicit adverse reactions that, while not being unique, are particularly associated with that drug. For example, felbamate may cause aplastic anaemia and fulminant liver failure, lamotrigine is prone to cause skin rash, and oxcarbazepine may cause symptomatic hyponatraemia. Topiramate and zonisamide cause kidney stones, and vigabatrin may induce psychiatric syndromes. Although highly diverse in structure and activity, these newer drugs offer new possibilities for treating refractory epilepsy. However, since no single factor can dictate the choice of drug nor predict the success of treatment, prescribing of these rather expensive drugs has to depend upon careful consideration of the aims of treatment, the characteristics of the drug and the needs of the individual patient.     

温压补偿在CS3000中的应用

结合横河CS3000系统的使用情况,介绍了CS3000系统利用压力和温度检测点实现温度压力补偿功能,CS3000系统组态过程及功能块的运用等。     

无荷载状况下泡沫混凝土裂缝控制的研究

研究了水胶比、粉煤灰、PP纤维和高性能膨胀剂对无荷载状况下泡沫混凝土力学性能、收缩性能的影响.结果表明,泡沫混凝土在水化中后期表现为收缩的特征;在水胶比为0.3～0.5时,水胶比越大,最终泡沫混凝土的收缩越小,当水胶比大于0.5或小于0.2时,28 d收缩量都减小.乱向分布的纤维可以略微减小泡沫混凝土的收缩;一定掺量的膨胀剂可以有效地补偿泡沫混凝土变形收缩,在水化早期实现泡沫混凝土无收缩.     

地表水源热泵塑料螺旋管换热器面积设计

现有地表水源热泵换热器设计资料粗糙且不完全符合我国地表水的特点,应用误差较大.本文通过塑料螺旋管换热器设计计算简化数学模型的大量数值计算,可知在工程设计值范围内,影响其换热能力的显著因素是换热器进出口温差和地表水体流速,而换热介质种类、换热介质流速和地表水体温度等因素对换热器换热能力的影响不大.在此基础上,给出了供热、供冷工况的基本线算图和换热器进出口温差的修正系数公式、地表水体流速修正系数表.在保持基本线算图简便特性的同时,大大扩展了线算图的使用范围.本文结论可为我国地表水源热泵设计提供参考.     

实施民用建筑节能标准的经济和环境影响测算研究

建立了实施民用建筑节能标准的经济和环境影响测算模型.与以往的粗略估计不同,该模型将实施民用建筑节能标准与其引起的环境经济结构变化相联系,采用4个指标评价实施民用建筑节能标准的直接经济影响、5个指标评价直接环境影响、3个指标评价完全经济影响.在两种情境假定下,应用模型进行了测算.然后对模型中的主要参数和变量进行了敏感度分...     

岷江百合与兰州百合鳞茎中多酚组分及其生物活性

为研究百合的抗氧化和抑菌活性,以野生岷江百合和兰州百合为材料,采用比色法、高效液相色谱法(HPLC)和比浊法对其鳞茎中总多酚、黄酮、黄烷醇、单体酚组分及含量、抗氧化能力和抑菌活性进行分析。结果表明:两种百合鳞茎中均富含多酚但种间存在显著差异(p<0.05),岷江百合鳞茎中总多酚、黄酮和黄烷醇的含量分别是兰州百合含量的2.07、2.25、3.16倍;在两种百合鳞茎中检测出14种单体酚,其中原矢车菊素B2含量最高,在岷江百合和兰州百合中分别达到了37.60、20.60 mg·kg^-1,除没食子酸外,岷江百合鳞茎中其他被检测出的单体酚含量是兰州百合的1.43~41.84倍;两种百合鳞茎多酚提取物均具有一定的抗氧化和抑菌活性,且岷江百合的抗氧化和抑菌活性均显著高于兰州百合(p<0.05),是兰州百合的1.40~14.40倍。野生岷江百合鳞茎多酚提取物具有抗氧化和抑菌双重作用,可作为天然抗氧化剂、抗菌药物应用于食品和医药业,具有良好的开发应用前景。     

短切玻璃纤维(GF)增强PET复合材料的研究

通过溶液法制备了短切玻璃纤维增强PET复合材料;研究了短切玻璃纤维含量和长度对PET／GF复合材料强度的影响;并对试样冲击断口的显微结构和断裂形态进行了分析。结果表明,复合材料的强度随玻璃纤维含量的增加先提高后降低,即出现极值,随玻璃纤维长度的增加其强度略有提高;且要制得玻璃纤维分布均匀的PET／GF复合材料;KH550是PET／GF复合体系的良好偶联剂。     

基于EPP模式下的数据采集系统

介绍了一种基于并口EPP模式通讯的数据采集系统的设计方法,该系统以ADSP2 1 81、E PLD为核心器件,AD7331 1芯片为模拟信号输入输出接口,非常适合便携式数据采集系统     

The effect of oxidative stress on structural transitions of human erythrocyte ghost membranes

The influenza virus hemagglutinin (HA) contains three highly conserved cysteine residues at positions 551, 559, and 562 close to the carboxyl-terminus of the HA2 subunit which serve as palmitylation sites. Wild-type HA of influenza virus A/FPV/Rostock/34 (H7N1) and HA permutated by exchange of the acylated cysteine to serine residues were expressed in CV-1 cells by a SV40 vector system. Since density of immunostained HA on the cell surface measured by flow cytometric analysis did not differ between wild-type and acylation mutants, it was possible to compare acylation mutants and wild-type HA for their capacity to induce membrane fusion at low pH. The following observations were made: (1) lateral diffusion of a lipid-like fluorophore (R-18) from the erythrocyte membrane to the plasma membrane of cells expressing HA on the surface occurred equally well with mutants and wild type. (2) Diffusion of a low-molecular-weight fluorescent water-soluble probe (calcein) from erythrocytes into the cytoplasm of HA-expressing cells was not altered either. (3) However, depending on the position and the number of the deleted acylation sites, the mutants showed a reduced ability to induce syncytia. The data indicate that deacylation of the cytoplasmic tail has no measurable effect on the capacity of HA to induce membrane fusion and pore formation but that it suppresses syncytia formation.